Effects of high-grain diet feeding on mucosa-associated bacterial community and gene expression of tight junction proteins and inflammatory cytokines in the small intestine of dairy cattle
Effects of high-grain diet feeding on mucosa-associated bacterial community and gene expression of tight junction proteins and inflammatory cytokines in the small intestine of dairy cattle
复制标题
高粮饲喂对奶牛小肠粘膜相关细菌群落及紧密连接蛋白和炎症细胞因子基因表达的影响
DOI：
10.3168/jds.2021-21355
复制
发表时间：
2022-07-21
影响因子：
3.5
通讯作者：
Mao, S.
中科院分区：
文献类型：
--
作者：
Lai, Z.;Lin, L.;Mao, S.
本研究旨在研究饲喂高粒饲粮的奶牛小肠黏膜相关菌群组成、小肠上皮形态、连接蛋白和炎性细胞因子基因表达的变化。选取12头泌乳中期的瘤胃空心荷斯坦奶牛，随机饲喂常规（CON）饲粮（40%精料，干物质基础）或HG饲粮（60%精料，干物质基础）4周。饲喂试验结束后，屠宰所有奶牛，利用16S全长扩增子测序检测小肠黏膜相关细菌群落的变化。利用实时定量PCR技术研究小肠上皮紧密连接蛋白和炎性细胞因子的基因表达。非度量多维标度图的结果显示，HG饮食改变了空肠和回肠粘膜相关细菌群落的组成。HG的摄食只增加了空肠黏膜相关细菌群落的可操作分类单位数量。在属水平上，HG饲粮增加了十二指肠黏膜中未培养的琥珀弧菌科和无毛菌科的丰度，而空肠黏膜中绒毛菌和硒单胞菌的比例增加。与CON组相比，HG组空肠和回肠粘膜中乙酰化肌的比例均高于CON组。PICRUSt2 （version 2.2.0-b）分析表明，HG饮食增加了空肠黏膜中与外源生物降解相关的基因丰度和回肠黏膜中与免疫疾病相关的基因丰度。此外，HG组空肠和回肠食糜中li-葡多糖含量较高。HG饲喂引起空肠上皮occludin和ZO-1 mRNA表达下调，回肠上皮claudin-1、claudin-4和ZO-1 mRNA表达下调。此外，HG饮食导致空肠上皮IL-1 β、IL-2和ifn - γ mRNA表达升高，但回肠上皮IL-2和ifn - γ mRNA表达升高。相关分析显示，HG饲喂期间空肠和回肠上皮细胞因子表达的变化可能与脂多糖水平和黏膜相关细菌群落的改变有关。这些发现表明，居住在小肠中的微生物群对宿主奶牛的健康有益。
The objective of this study was to investigate changes in the composition of mucosa-associated bacterial com-munity, the morphology of the small intestinal epithe-lia, and the gene expressions of junction proteins and inflammatory cytokines in the small intestines of dairy cattle fed a high-grain (HG) diet. A total of 12 rumi-nally cannulated Holstein cows in mid-lactation were randomly fed either a conventional (CON) diet (40% concentrate, dry matter basis) or an HG diet (60% concentrate, dry matter basis) for 4 wk. At the end of the feeding trial, all the cows were slaughtered and then examined for changes in the small intestinal mucosa-associated bacterial communities using 16S full-length amplicon sequencing. Furthermore, the gene expression of tight junction proteins and inflammatory cytokines in the small intestinal epithelium were studied using real-time quantitative PCR. The results of nonmetric multidimensional scaling plots showed that an HG diet altered the composition of mucosa-associated bacterial communities in the jejunum and ileum. The HG feeding only increased the numbers of operational taxonomic units in the mucosa-associated bacterial community in the jejunum. At the genus level, the HG diet increased the abundance of uncultured Succinivibrionaceae and Lachnospiraceae incertae sedis in the duodenal mucosa, whereas the proportions of Veillonella and Selenomonas increased in the jejunal mucosa. Compared with the CON group, the proportions of Acetitomaculum in both the jejunal and the ileal mucosa were higher in the HG group. Analysis via PICRUSt2 (version 2.2.0-b) sug-gested that the HG diet increased the abundance of genes related to biodegradation of xenobiotics in the jejunal mucosa and the abundance of genes related to immune disease in the ileal mucosa. Additionally, the group fed an HG diet had higher concentrations of li-popolysaccharides in the jejunal and ileal digesta. The HG feeding caused a downregulation of the mRNA ex -pression of occludin and ZO-1 in the jejunal epithelium, as well as of claudin-1, claudin-4, and ZO-1 in the ileal epithelium. Moreover, the HG diet caused an increase in the mRNA expression of IL-1 beta, IL-2, and IFN-gamma in the jejunal epithelium, but a higher expression of IL-2 and IFN-gamma in the ileal epithelium. Correlation analysis revealed that the alteration of lipopolysaccharide levels and mucosa-associated bacterial community might partly contribute to changes in the expression of the epithelial cytokines in the jejunum and ileum during HG feeding. These findings suggest that microbiota residing in the small intestine provide essential health benefits to host dairy cattle.